A. Technical Field
The present invention relates to solid-state lighting systems and, more particularly, to systems, devices, and methods of eliminating electromagnetic interference (EMI) in LED lamps and enabling operation with both magnetic and electronic transformers.
B. Background of the Invention
In a variety of lighting applications, environmentally friendly and efficient Light Emitting Diode (LED) lamps with long lifetimes unmatched by incandescent or fluorescent lamps are rapidly replacing conventional lamps. The MR16 halogen lamp, for example, which utilizes inefficient filament heating when generating light has been around since the 1960's, and was designed to run at three different power levels 20 W, 25 W, and 50 W. Today, most halogen-based lamps are powered by high power electronic transformers that are incompatible with LED lamps that are rated for considerably lower input power levels. This makes retrofitting halogen lamp fixtures with LED lamps an ongoing challenge.
Some lighting system designs allow LED lamps to operate with both magnetic and electronic transformers. However, operating an LED lamp with a magnetic transformer necessitates an electromagnetic interference (EMI) filter in order to pass various national and international EMI tests. Testing is performed according to standards that are generally imposed by governmental requirements, such as FCC Class B in the United States or EN55015 in Europe. Unfortunately, adding filtering negates the achieved compatibility between the LED lamp and the electronic transformer.
Possible solutions to avoid EMI issues include replacing electronic transformers with magnetic transformers that power EMI-filtered LED lamps, or replacing electronic transformers with LED-compatible ones. However, since most transformers are built into the lighting fixture, a consumer who wishes to retrofit a pre-existing lighting fixture is faced with limited access to limited access points, such as a few pins. Therefore, such solutions require the help of qualified technicians or electricians familiar with local and national electrical codes regarding installation, which increases the cost of the overall lighting system and is, therefore, rather impracticable for the retrofit market.
What is needed are systems and methods that overcome the above described limitations and allow LED lamps to be retrofitted with both magnetic and electronic transformers in a manner that allows to pass EMI testing.